Over the years, various machines have been developed for protective and/or display packaging of articles including skin packaging machines, curtain coating machines, blister packaging machines, and the like.
In blister packaging, the film is initially preformed abut a suitable die to provide a multiplicity of pockets which may or may not closely conform to the shape of the articles to be packaged. The thus formed film is cut into individual blisters which are then placed in a suitable platen providing receptacles therefor in the desired spaced realtionship, the articles to be packaged are placed in the blisters, and a cardboard substrate is bonded to the flanges of the blisters by adhesive, application of heat, or other suitable means. Finally, the substrate is cut about the individual blisters to provide the individual packages.
In skin packaging, the film is heated to the point of plasticity and is brought to a point closely adjacent the substrate and actually formed about the articles on the substrate and then bonded to the substrate. This produces a close fitting sheath and this bonding technique generally does not require a separate adhesive if the proper materials are employed. Although a number of machines have been developed to provide relatively high speed operations by providing both forming and cutting sections at separate stages in a single unit through which the substrates are conveyed automatically, most commercial machines have employed intermittent movement of the substrate to allow the forming and cutting operations to take place at fixed points along the path of travel of the substrate therethrough. Moreover, it has been proposed in some machines to have the clamping frame or a vacuum platen for forming the film move relative to the frame of the machine. Illustrative of machines intended to provide continious or semicontinuous high speed operation are those shown in U.S. Pat. Nos.:
______________________________________ Patentee Patent No. Grant Date ______________________________________ Rorer 3,377,770 April 16, 1968 Stone 3,587,200 June 28, 1971 Parvin 3,668,820 June 13, 1972 Canamero et al 3,673,760 July 4, 1972 Tartarini 3,902,302 Sept. 2, 1975 Reid 3,930,350 Jan. 6, 1976 ______________________________________
As of the present time, there has been commercially available no packaging machine of the type wherein the substrates advance substantially continuously and the forming and cutting operations occur without interruption of the progress of the substrates through the packaging machine on the conveying means. Moreover, there has been no such machine in which the speed of advance and operation of the forming and cutting stages may be quickly and conveniently adjusted to compensate for different packaging materials and/or conditions.
It is an object of the present invention to provide a novel packaging machine for forming enclosures to encapsulate articles between a film and a substrate and wherein heating, forming and cutting stages are combined and operative as the film advances therethrough substantially continuously.
It is also an object to provide such a packaging machine in which the speed of advance and the speed of the forming and cutting operations may be readily and conveniently adjusted to compensate for variation in materials and/or packaging conditions.
Another object is to provide such a packaging machine in which advancement of components and forming and cutting operations are simultaneously conducted and controlled by simple and rugged adjustable drive and control means.
A further object is to provide such a packaging machine in which misalignment of skin packaged articles upon the substrate may be determined rapidly and conveniently prior to cutting stage.